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A New Brain Mitochondrial Sodium-Sensitive Potassium Channel: Effect of Sodium Ions on Respiratory Chain Activity Publisher Pubmed



Fahanikbabaei J1, 2 ; Rezaee B2 ; Nazari M3 ; Torabi N3 ; Saghiri R4 ; Sauve R5 ; Eliassi A2, 3
Authors
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Authors Affiliations
  1. 1. Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, 1419733141, Iran
  2. 2. Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, 1985717443, Iran
  3. 3. Department of Physiology, Shahid Beheshti University of Medical Sciences, Tehran, 1985717443, Iran
  4. 4. Department of Biochemistry, Pasteur Institute of Iran, Tehran, 1985717443, Iran
  5. 5. Department of Pharmacology and Physiology, Membrane Protein Research Group, Universite de Montreal, Montreal, H3C 3J7, QC, Canada

Source: Journal of Cell Science Published:2020


Abstract

We have determined the electropharmacological properties of a new potassium channel from brain mitochondrial membrane using a planar lipid bilayer method. Our results show the presence of a channel with a conductance of 150 pS at potentials between 0 and −60 mV in 200 mM cis/50 mM trans KCl solutions. The channel was voltage independent, with an open probability value of approximately 0.6 at different voltages. ATP did not affect current amplitude or open probability at positive and negative voltages. Notably, adding iberiotoxin, charybdotoxin, lidocaine or margatoxin had no effect on the channel behavior. Similarly, no changes were observed by decreasing the cis pH to 6. Interestingly, the channel was inhibited by adding sodium in a dose-dependent manner. Our results also indicated a significant increase in mitochondrial complex IV activity and membrane potential and a decrease in complex I activity and mitochondrial ROS production in the presence of sodium ions. We propose that inhibition of mitochondrial potassium transport by sodium ions on potassium channel opening could be important for cell protection and ATP synthesis. © 2020 Company of Biologists Ltd. All rights reserved.
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